In order to provide a light emitting lamp that makes it possible to control the light emitting lamp to be at a target temperature, for a light emitting lamp including a valve portion 2 and sealing portions 3a and 3b, a quantity of power-consumption-dependent heat losses due to convection and conduction of the valve portion 2, the inside diameter of the valve portion 2, and the diameter and the length of the sealing portions 3a and 3b are determined in advance, and the outside diameter of the valve portion 2 is determined on the basis of these quantity of heat losses, inside diameter of valve portion, diameter, of sealing portions, and length of sealing portions, so that an average value of inner temperatures of the light valve portion 2 at the time of luminescence falls within a range from 900 to 1000° C.